Health Library

Garlic

Botanical name(s):

Allium sativum. Family: Liliaceae

General description

Garlic consists of fresh or dried bulbs of the botanical plant Allium sativum, which is cultivated worldwide. The bulb or clove is the part of the plant most commonly used, but sometimes garlic oil is used. Garlic is best stored hung in plaits in a dry place.

Garlic contains alliin, which, when ground, produces the strong-smelling, potent antibacterial agent allicin. In addition to its supposed antibacterial properties, garlic is claimed to provide protection against atherosclerosis and stroke because of its ability to inhibit platelet aggregation and decrease high blood pressure and high cholesterol.

Medically valid uses

Some studies using animals suggest that garlic may improve insulin release in people with diabetes, but there is no scientific evidence to support this in humans.

There is some evidence that garlic may improve the elasticity of the aorta and decrease the formation of atherosclerotic plaque.

There is some evidence that garlic can lower cholesterol levels, however the effect is slight. But a recent study funded by the National Center for Complementary and Alternative Medicine found that garlic had no effect on cholesterol levels.

Some clinical research shows that taking garlic orally can modestly reduce blood pressure in patients with hypertension and in people with normal blood pressure

There is good evidence that garlic decreases the ability of blood platelets to form clots.

Unsubstantiated claims

Please note that this section reports on claims that have NOT yet been substantiated through scientific studies.

Garlic contains allicin, a potent antibiotic that is released when cloves are crushed or chewed. Garlic has been used as an antiseptic, antibacterial, and antifungal agent. It is claimed to help the body resist or destroy viruses and other microorganisms by enhancing the body's immune system.

Garlic is also claimed to fight infection, as well as build up strength.

Garlic may help treat chronic bronchitis, respiratory catarrh, recurrent colds and respiratory infections, chronic episodes of earache, sore throat, sinus problems, and influenza. Garlic is thought to be useful in treating yeast infections and intestinal worms, and to have laxative properties.

Dosing format

Garlic is available fresh, dried in capsule form (enteric-coated capsules are easiest for the body to absorb), as an extract and as odorless supplements. The quality of commercial preparations varies greatly.

Use as directed on the label.

Side effects, toxicity, and interactions

Garlic has a strong taste and odor, and raw garlic can cause stomach or intestinal upset in some people. Odorless garlic supplements eliminate offending taste and odor and may reduce or eliminate gastrointestinal upset. Some people are allergic to garlic. When taken in large amounts, garlic may have toxic effects, causing stomach ulcers and anemia.

There are no known significant food or drug interactions associated with garlic.

Additional information

Click here for a list of reputable websites with general information on nutrition.